With the development of personal computers in recent years, especially with the development of portable personal computers, the demand for liquid crystal display devices, especially for color liquid crystal display devices, tends to rise. Color liquid crystal display devices are expensive, however, so that there is an increasing request for cost reduction. Especially, the request for cost reduction of color filters, which are costly, is very high. Typical examples of the structure of color filters used in liquid crystal display devices, will be described using FIGS. 1A and 1B.
In general, a color liquid crystal display device (101) has a structure in which, as shown in FIG. 1A, a color filter 1 and an electrode substrate 2 (such as a TFT substrate) are faced each other; a gap 3 having a width of about 1 to 10 μm is provided therebetween and filled with a liquid crystal compound L; and the periphery of these parts is hermetically sealed with a sealing material 4. The color filter 1 has a structure in which, on a transparent substrate 5, a light-shielding member 6, a pixel 7, a protecting film 8 and a transparent electrode film 9 are stacked in this order from the closest to the transparent substrate, the light-shielding member 6 being formed in a predetermined pattern to shield the boundary portion between pixels from light, and the pixels 7 being formed in several colors (normally three primary colors of red(R), green (G) and blue(B)) and arranged in a predetermined order. Orientation films 10 are provided on the inner surface sides of the color filter 1 and the electrode substrate 2 which faces the color filter. A spacer is provided in the gap 3 to keep a cell gap between the color filter 1 and the electrode substrate constant and uniform. As the spacer, pearls 11 having a fixed particle diameter are dispersed, or as shown in FIG. 1B, a columnar spacer 12 having a height that corresponds to the cell gap, is formed in a region which is inside the color filter and overlaps the position where the light-shielding member 6 is formed. Finally, the light transmittance of each of the pixels colored in different colors or that of a liquid crystal layer disposed behind the color filter is controlled to obtain a color image.
A conventional color filter production method is a pigment dispersing method. In this method, first, a photosensitive resin layer containing dispersed pigments is formed on a substrate and then patterned to obtain a monochromatic pattern. This process is repeated three times to form color filter layers in red (R), green (G) and blue (B). This method, however, needs to repeat the same process three times to form the three colors of R, G and B, so that there is a problem of high cost; moreover, due to the repeating of the same process, there is a problem of poor yield.
A method for producing a color filter is described in Patent Literature 1, which was succeeded in overcoming the problems in such a manner that a color ink containing a thermosetting resin is ejected onto a substrate by the ink-jet method and heated to form a colored layer (pixel).